Angle-Resolved Loss of Landau Quasiparticles in 2D Hubbard Model

The problem of weakly correlated electrons on a square lattice is studied theoretically. A simple renormalization group scheme for the angle-resolved weight Z of the quasiparticles at the Fermi surface is presented and applied to the Hubbard model. Upon reduction of the cutoff the Fermi surface is progressively destroyed from the van Hove points toward the zone diagonals. Due to the renormalized Z, divergences of both antiferromagnetic and superconducting correlation functions are suppressed at the critical scale, where the interactions diverge.